Improved thermoplastic coated paperboard web

Abstract

A web suitable for forming liquid-containing paperboard cartons wherein a thermoplastic film is extruded onto a paperboard web, the film having thick strips deposited over those areas of the web which ultimately form the bottom portion of the cartons.

We claim: 
     
       1. An article adapted for the manufacture of thermoplastic coated paperboard carton blanks from which cartons can be formed, said cartons having a bottom structure formed by folding panels on a major horizontal bottom score line, the article consisting of: an elongated paperboard web of indeterminate length having a predetermined width which is sufficient to accommodate a plurality of longitudinally extending adjacent rows of unformed carton blanks thereacross,   at least one longitudinally extending area in said web including portions of unformed blanks in two of said adjacent rows, and within which area the entire bottom structure including the major horizontal score lines and folding panels for each of the blanks in said two adjacent rows are to be formed,   a unitary extruded polyethylene film coating one said of said web, said film having a plurality of longitudinally extending strips of varying thickness, a strip of greater thickness covering said longitudinally extending area of said web such that said strip of greater thickness is of a width to cover the entire to be formed bottom structures including the major horizontal score lines and folding panels of said unformed blanks in said two adjacent rows, and at least one strip of lesser thickness covering the remainder of said web,   a coating on another side of said web, and   said coated web being rolled upon itself to form a generally cylindrical roll.   
     
     
       2. An article as in claim 1 wherein said thicker strip is about 0.0015 inches in thickness and said strip of lesser thickness has a thickness of about 0.00075 inches. 
     
     
       3. An article adapted for the manufacture of thermoplastic coated paperboard cartons each having a bottom structure formed by folding panels on a major horizontal bottom score line, the article consisting of: an elongated paperboard web of indeterminate length and having a predetermined width between generally parallel elongated edges, said width being sufficient to accommodate at least one row of unformed carton blanks thereacross,   at least one longitudinally extending area in said web generally parallel to said edges and within which area the entire bottom structures, including the major horizontal score line and said folding panels are to be formed,   a unitary extruded polyethylene film coating one side of said web, said film having longitudinally extending strips of varying thicknesses, a respective strip of greater thickness covering said longitudinally extending area and at least one respective strip of lesser thickness covering the remainder of said web,   a coating on another side of said web, and   said coated web being rolled upon itself to form a generally cylindrical roll.   
     
     
       4. An article as in claim 3 wherein said thicker strip is about 0.0015 inches thick and said strip of lesser thickness has a thickness of about 0.00075 inches. 
     
     
       5. An article adapted for the manufacture of thermoplastic coated paperboard cartons each having a bottom structure formed by folding panels on a major horizontal bottom score line, the article consisting of: an elongated paperboard web of indeterminate length and having a predetermined width between generally parallel elongated edges, said width being sufficient to accommodate at least one row of unformed carton blanks thereacross,   at least one longitudinally extending area in said web generally parallel to said edges and within which area the entire bottom structures, including the major horizontal score line and said folding panels are to be formed,   a unitary extruded polyethylene film coating one side of said web, said film having longitudinally extending strips of varying thicknesses, a respective strip of greater thickness covering said longitudinally extending area and at least one respective strip of lesser thickness covering the remainder of said web,   a coating on another side of said web,   said coated web being rolled upon itself to form a generally cylindrical roll, and   said article being formed by the process of selectively regulating the pressure of the polyethylene within a die extruding means and thereafter extruding said unitary polyethylene film onto said web through a uniform die orifice having edges uniformly spaced apart throughout the length of the die orifice, whereby said unitary extruded polyethylene film takes on said profile of varying thickness across its width.   
     
     
       6. An article as in claim 5 wherein said thicker strip is about 0.0015 inches thick, and said strip of lesser thickness is about 0.00075 inches thick. 
     
     
       7. An article adapted for the manufacture of thermoplastic coated paperboard carton blanks from which cartons can be formed, said cartons having a bottom structure formed by folding panels on a major horizontal bottom score line, the article consisting of: an elongated paperboard web of indeterminate length having a predetermined width which is sufficient to accommodate a plurality of longitudinally extending adjacent rows of unformed carton blanks thereacross,   at least one longitudinally extending area in said web including portions of unformed blanks in two of said adjacent rows, and within which area the major horizontal score lines and folding panels for each of the blanks in said two adjacent rows are to be formed,   a unitary extruded polyethylene film coating one side of said web, said film having a plurality of longitudinally extending strips of varying thickness, a strip of greater thickness covering said longitudinally extending area of said web such that said strip of greater thickness is of a width to cover the entire to-be-formed bottom structures including the major horizontal score lines and folding panels of said unformed blanks in said two adjacent rows, and at least one strip of lesser thickness covering the remainder of said web,   a coating on another side of said web,   said coated web being rolled upon itself to form a generally cylindrical roll, and   said article being formed by the process of extruding said unitary extruded polyethylene film onto said web wherein said process includes the step of selectively regulating the pressure of the polyethylene within a die extruding means and thereafter extruding said unitary polyethylene film onto said web through a uniform die orifice having edges uniformly spaced apart throughout the length of the die orifice, whereby said unitary extruded polyethylene film takes on a profile, across its width, of said plurality of longitudinally extending strips of varying thickness.   
     
     
       8. An article as in claim 7 wherein said thicker strip is about 0.0015 inches thick, and said strip of lesser thickness is about 0.00075 inches thick. 
     
     
       9. An article adapted for the manufacture of thermoplastic coated paperboard cartons each having a bottom structure formed by folding panels on a major horizontal bottom score line, the article consisting of: an elongated paperboard web of indeterminate length and having a predetermined width between generally parallel elongated edges, said width being sufficient to accommodate at least one row of unformed carton blanks thereacross,   at least one longitudinally extending area in said web generally parallel to said edges and within which area the entire bottom structures, including the major horizontal score line and said folding panels are to be formed,   a unitary extruded polyethylene film coating one side of said web, said film having longitudinally extending strips of varying thicknesses, a respective strip of greater thickness covering said longitudinally extending area and at least one respective strip of lesser thickness covering the remainder of said web,   a coating on another side of said web,   said coated web being rolled upon itself to form a generally cylindrical roll, and which can thereafter be unwound, scored, and cut to form coated carton blanks, and   said article being formed by the process of extruding said coating onto said web, wherein said process includes the steps, introducing said polyethylene into an extrusion die, regulating the pressure of the polyethylene within the die, prior to exit therefrom, so as to cause said polyethylene to take on, upon exiting said die, a profile of varying thickness across its width, and extruding said unitary polyethylene film onto said web through a uniform die orifice having edges uniformly spaced apart throughout the length of the die orifice, said polyethylene film taking on, after said extrusion, said profile of varying thickness.   
     
     
       10. An article adapted for the manufacture of polyethylene coated paperboard carton blanks consisting of: an elongated paperboard web of indeterminate length having a predetermined width sufficient to accommodate a plurality of longitudinally extending adjacent rows of unformed carton blanks thereacross,   at least one longitudinally extending area in said web within which the entire bottom structures, including major horizontal score lines and folding panels for each of the blanks in each of said adjacent rows, are to be formed,   a unitary extruded polyethylene film coating one side of said web, said film having an area of greater thickness covering said longitudinally extending area in said web and an area of lesser thickness covering the remaining area of said adjacent rows, said area of greater thickness being about twice as thick as said area of lesser thickness,   a coating on another side of said web,   said web, with said film of differing coating thicknesses, being rolled upon itself to form a generally cylindrical roll, which can thereafter be unwound, scored and cut to form coated carton blanks, and   whereby said article provides an increased resistance to leakage in the to-be-formed cartons only in the area where such carton will be most likely to leak, and resulting in a reduction of the total amount of polyethylene used over the whole to-be-formed carton as compared with a uniformly coated carton having a level polyethylene coating of a sufficient thickness to provide a carton of equal resistance to leakage in the area most likely to leak.   
     
     
       11. An article as in claim 10 wherein said strip of greater thickness is about 0.0015 inches thick and said strip of lesser thickness is about 0.00075 inches thick. 
     
     
       12. An article adapted for the manufacture of polyethylene coated paperboard cartons each having a bottom structure formed by folding panels on a major horizontal bottom score line, consisting of: an elongated paperboard web of indeterminate length, having a predetermined width between generally parallel elongated edges, said width being sufficient to accommodate at least one row of to-be-formed carton blanks thereacross,   at least one longitudinally extending area in said web generally parallel to said edges and within which area the entire bottom structures, including the major horizontal score line and said folding panels are to be formed,   a unitary extruded polyethylene film coating one side of said web, said film having longitudinally extending areas of varying thickness, an area of greater thickness covering said longitudinally extending area in said web and an area of lesser thickness covering the remainder of said web, said thicker area being about twice as thick as said area of lesser thickness,   a coating on another side of said web,   said web, with said film of differing thicknesses, being rolled upon itself to form a generally cylindrical roll which can thereafter be unwound, scored and cut to form coated carton blanks, and   whereby said article provides an increased resistance to leakage in the to-be-formed cartons only in the area where such carton will be most likely to leak, and resulting in a reduction of the total amount of polyethylene used over the whole to-be-formed carton as compared with a uniformly coated carton having a level polyethylene coating of a sufficient thickness to provide a carton of equal resistance to leakage in the area most likely to leak.   
     
     
       13. An article as in claim 12 wherein said thicker area is about 0.0015 inches thick and said area of lesser thickness is about 0.00075 inches thick. 
     
     
       14. An article adapted for the manufacture of polyethylene coated paperboard cartons having a bottom structure formed by folding panels on a major horizontal bottom score line, consisting of: an elongated paperboard web of indeterminate length, having a predetermined width between generally parallel elongated edges, said width being sufficient to accommodate at least one row of the to-be-formed carton blanks thereacross,   at least one longitudinally extending area in said web generally parallel to said edges and within which area the entire bottom structures, including the major horizontal score line and said folding panels of said row are to be formed,   a unitary extruded polyethylene film coating one side of said web, said film having a longitudinally extending area of greater thickness covering said longitudinally extending area and an area of lesser thickness covering the remainder of said web, said thicker area being about twice as thick as said area of lesser thickness,   a coating on another side of said web,   said web, with said film of differing thicknesses, being rolled upon itself to form a generally cylindrical roll which can thereafter be unwound, scored and cut to form coated carton blanks,   said article being formed by the process of selectively regulating the pressure of the polyethylene within a die extruding means and thereafter extruding said unitary polyethylene film onto said web through a uniform die orifice having edges uniformly spaced apart throughout the length of the die orifice, whereby said unitary extruded polyethylene film takes on said profile of varying thickness across its width, and   whereby said article provides an increased resistance to leakage in the to-be-formed cartons only in the area where such carton will be most likely to leak, and resulting in a reduction of the total amount of polyethylene used over the whole to-be-formed carton as compared with a uniformly coated carton having a level polyethylene coating of a sufficient thickness to provide a carton of equal resistance to leakage in the area most likely to leak.   
     
     
       15. An article as in claim 14 wherein said thicker area is about 0.0015 inches thick and said area of lesser thickness is about 0.00075 inches thick. 
     
     
       16. An article adapted for the manufacture of polyethylene coated paperboard carton blanks from which cartons can be formed, said cartons having a bottom structure formed by folding panels on a major horizontal bottom score line, consisting of: an elongated paperboard web of indeterminate length having a predetermined width which is sufficient to accommodate a plurality of longitudinally extending adjacent rows of unformed carton blanks thereacross,   at least one longitudinally extending area in said web within which area the major horizontal score lines and folding panels for each of the blanks in said adjacent rows are to be formed,   a unitary extruded polyethylene film coating one side of said web, said film having a plurality of longitudinally extending areas of varying thickness, an area of greater thickness covering the area of the to-be-formed bottom structures, including the major horizontal score lines and folding panels of said to-be-formed blanks in said adjacent rows, and an area of lesser thickness covering the remainder of said web, said thicker area being about twice as thick as said area of lesser thickness,   a coating on another side of said web,   said coated web being rolled upon itself to form a generally cylindrical roll, which can thereafter be unwound, scored and cut to form coated carton blanks,   said article being formed by the process of extruding said unitary extruded polyethylene film onto said web wherein said process includes the step of selectively regulating the pressure of the polyethylene within a die extruding means and thereafter extruding said unitary polyethylene film onto said web through a uniform die orifice having edges uniformly spaced apart throughout the length of the die orifice, whereby said unitary extruded polyethylene film takes on a profile, across its width, of said plurality of longitudinally extending strips of varying thickness, and   whereby said article provides an increased resistance to leakage in the to-be-formed cartons only in the area where such carton will be most likely to leak, and resulting in a reduction of the total amount of polyethylene used over the whole to-be-formed carton as compared with a uniformly coated carton having a level polyethylene coating of a sufficient thickness to provide a carton of equal resistance to leakage in the area most likely to leak.   
     
     
       17. An article as in claim 16 wherein said thicker area is about 0.0015 inches thick and said area of lesser thickness is about 0.00075 inches thick. 
     
     
       18. An article adapted for the manufacture of polyethylene coated paperboard cartons each having a bottom structure formed by folding panels on a major horizontal bottom score line, consisting of: an elongated paperboard web of indeterminate length, having a predetermined width between generally parallel elongated edges, said width being sufficient to accommodate at least one row of unformed carton blanks thereacross,   at least one longitudinally extending area in said web generally parallel to said edges and within which area the entire bottom structures, including the major horizontal score line and said folding panels are to be formed,   a unitary extruded polyethylene film coating one side of said web, said film having longitudinally extending areas of varying thicknesses, an area of greater thickness covering said longitudinally extending area in said web at least one area of lesser thickness covering the remainder of said web, said thicker area being about twice as thick as said area of lesser thickness,   a coating on another side of said web,   said web, with said film of different thicknesses, being rolled upon itself to form a generally cylindrical roll, and which can thereafter be unwound, scored, and cut to form coated carton blanks,   said article being formed by the process of extruding said coating onto said web, wherein said process includes the steps, introducing said polyethylene into an extrusion die, regulating the pressure of the polyethylene within the die, prior to exit therefrom, so as to cause said polyethylene to take on, upon exiting said die, a profile of varying thickness across its width, and extruding said unitary polyethylene film onto said web through a uniform die orifice having edges uniformly spaced apart throughout the length of the die orifice, said polyethylene film taking on, after said extrusion, said profile of varying thickness, and   whereby said article provides an increased resistance to leakage in the to-be-formed cartons only in the area where such carton will be most likely to leak, and resulting in a reduction of the total amount of polyethylene used over the whole to-be-formed carton as compared with a uniformly coated carton having a level polyethylene coating of a sufficient thickness to provide a carton of equal resistance to leakage in the area most likely to leak.   
     
     
       19. An article as in claim 18 wherein said area of greater thickness is about 0.0015 inches thick and said area of lesser thickness is about 0.00075 inches thick.